Terry was born in San Jose, California to Lorraine and Jack Mullen. He was a happy, curious, and energetic child who exhausted his parents and older sisters. At a young age, he developed a strong sense of social justice and empathy for human suffering. He graduated from Leland High School in 1987 and moved to Sonoma County to attend Santa Rosa Junior College. He later transferred to San Francisco State University, graduating in 1993 with a Bachelor's of Arts degree in Philosophy.

While he was a college student, Terry gained experience in the field of theatrical lighting, and also became politically active in human rights issues. Always brave, Terry traveled to Haiti in 1993 to be a human rights witness while the country was living under a military coup. He spent several years volunteering with Amnesty International.

After his college graduation, Terry became a respected and talented stagehand with Phoebus Lighting and later I.A.T.S.E Local 16. He met Angelique in 1995, and they were instantly inseparable. They married in 1998, and had two beautiful children.

Terry was an avid outdoorsman, activist, and baseball fan. He loved going to Giants games, especially with his children. Terry loved camping, hiking, and spending time outside whenever possible. His interests also included glass blowing, kayaking, and playing risk. Terry learned a little bit of Creole when he went to Haiti, but he would jokingly say he always wanted to learn Esperanto.

Terry was a wonderful and devoted husband, as well as a truly engaged and loving father. He was a beloved son, brother, friend and esteemed colleague. He is painfully missed by all who knew him! He is survived by his wife Angelique, their children, Daphne and Henry, his parents Jack and Lorraine Mullen of Bodega Bay, sister Kathy Dylina and her husband Gary Dylina of Benicia, and sister Shari Mullen and her husband Steve Tucker of Saratoga, as well as cousins, inlaws, and extended family.